Antisite defect types and temporal evolution characteristics of D0 ₂₂-Ni₃V structure: Studied by the microscopic phase field

Microscopic phase field simulation is performed to study antisite defect type and temporal evolution characteristic of D0₂₂-Ni₃V structure in Ni₇₅Al _x V_25-x ternary system. The result demonstrates that two types of antisite defect V_Ni and Ni_V coexist in D0₂₂ structure; however, the amount of Ni_V is far greater than V_Ni; when precipitates transform from D0₂₂ singe phase to two phases mixture of D0₂₂ and L1₂ with enhanced Al:V ratio, the amount of V_Ni has no evident response to the secondary L1₂ phase, while Ni_V exhibits a definitely contrary variation tendency: Ni_V rises without L1₂ structure precipitating from matrix but declines with it; temporal evolution characteristic and temperature dependent antisite defect V_Ni, Ni_V are also studied in this paper: The concentrations of the both defects decline from high antistructure state to equilibrium level with elapsed time but rise with elevated temperature; the ternary alloying element aluminium atom occupies both α and β sublattices of D0₂₂ structure with a strong site preference of substituting α site.